Clutch mechanism for multiple gear constant mesh transmission



Aug. 7, 1934. D. J. TINDELL ET AL 1,959,436 CLUTCH MECHANISM FORMULTIPLE GEAR CONSTANT MESH TRNSMSSIONy Filed May 1 5, 1933lISheefas-SheerI 1 www @NN IN VEN TORi Baum J. finden e;llJberJioodenougm m Egi mimi Il l y y ,v .i N. W www www W W W m... www5N v ow WI, @www l u.

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A TTORNE YS D. J. TINDELL Er AL 1,969,436 CLUTCH MECHANlSM FOR MULTIPLEGEAR CONSTANT MESH TRANSMISSION Aug. 7, 1934.

Filed May 15, 1935 4 Sheets-Sheet 2 a .W u u -v 3mm @F ma. @v W E a o@ sa bu M ,gpm

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Aug. 7, 1934. D. J. TINDELI. Er AL CLUTCH MECHANISM FOR MULTIPLE GEARCONSTANT MESH TRANSMISSION Filed May 15, 1935 4 Sheets-Sheet 3 h m W Wmm @www @m .m a www @m M S MH ji@ pas I; I w aman m3 .3. o 09mm 4 r :MwE auw@ m9 E im# 5d, D E a e www? Q w @Ni swg? EN @m um u Tg Aug- 7,1934. D. J. vTitular-:M Er AL 1,969,436

CLUTCH MECHANISM FOR MULTIPLE GEAR CONSTANT MESH`TRANSMISSION Filed May15, 1933 4 Sheets-Sheet 4 lkmiel J. Tindell e. wlbertoodennugh,

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Patented Aug. 7, 1934 UNITED. STATES Ginn YCONSTANT MESH TRANSMISSIONDaniel J.v 'rinden and Wiibei- H. Goddenough. i i Buffalo, N. Y.;

Application May 15, 193s, serial, No. @1,191

claims. (ci. 1oz-'11) This invention relates to speed changing devicesand it has particular relation to a multiple gear constant meshtransmission designed especially for installation in automotive vehiclesand 5 industrial machinery.

One object of the invention is to provide a variable speed gear in whichall of the working parts are positive in their action and not dependenton springs or friction for their operation, and

in which all of the working parts are easily replaceable and simple inconstruction.

Another object of the invention is to provide a transmission in whichall of the gears are in constant mesh at all times, and Ain which speedsmay be changed by slight straight forwardfor backward-movement of alever located in a convenient location, for example, upon the steeringpost of a vehicle.

All of the transmission gearing embodied in .20 the invention iscontained in a housing or casing .25 and a driven shaft arranged insubstantially axial alignment are provided with connecting means to asupplemental or intermediate transmission shaft arranged parallel tothedriving and driven shafts, the auxiliary shaft being hollow for re- Aceiving gear shifting elements necessary to produce the various gearratios desired in operating af motor vehicle. The transmissionfurtherincludes primary and secondary speedV changing gears in anydesired number depending upon the size of the transmission and the usevto which it is to be put. f

In the drawings: i Fig. 1 is a vertical section through the completetransmission structure showing the arrangement. 540 of the partsthereof;

Fig. 2 is a vertical section, on a larger scale, through a portion ofthe transmission structure for controlling setsof the primary gears;Fig. 3 is a cross section taken substantially along line Ill-III of Fig.2;

Fig. 4 is a cross section taken substantially along lline IV--IV of Fig.2;

Fig. 5 is a cross section taken along the line V-V ofvFig. 2;

6 is a'vertical section, on la. larger scale, through a. portionof thedevice andshowing a. shifting cage in its operative position fortransmission. of power;

Fig. 7 is a view similar to Fig. 2 showing the substantially 55 shiftingcage in a neutral position; f

O1-"FICE: f

. v letales 'Y A f Fig. 8 is a cross? section through the shift- .L

ingA cage taken substantially along the VIII-VIII of Fig. 7; I l

Fig. 9 is a crosssection through:A the shifting cage taken substantiallyalong the line IXIX of Fig. 6; Y

Fig. 10 Yis a. cross section taken substantially along line-X-f-X ofFig. 7;

Fig. 11 is a fragmentary elevation showing the positionV of controllevers with respect to a vehicle steering wheel; Y

Fig. 12 isa fragmentaryA cross section taken substantially along theline XII--XII of Fig. 1;

Fig. 13 is a plan of lever control members for effecting gear shiftingoperations `and mounted upon the vehicle steering column shown in sec,-ktion; and` Y, .y Y

Fig. 14 is a perspective of a cam block or shifting unit with'the cageomitted.

In practicing the invention a transmission housing or casing 2 0 isprovided for receiving a driven shaft'22 connected to a suitable machineo xvehicle axle (no t shown) to be operated and has bearings 23 and 2 5in the outer casing Wall and in'an intermediate bearing support Y26 ofthe casing, respectively. Transmission-gears 28, 29 and 30. different indiameter, are rigidly secured upon an inner end portion of the shaft 22between the bearings 23 and 25,' bymeans of av-key or spline connection32, and are further held against axial `movement. by the bearing 23 andbearing support 26. Thesegears intermesh with gears 35, 36 and 37respectively, also different in diameter, to complete afseriesof sets orpairs -of gears, each pair being in constant mesh. The gears 35, 36 and37 are mounted upon a hollow cylindrical shaft-38 that is journalled inbearings 39 at opposite sides of the housingZO and is pro-l vided withan intermediate bearing. in the bearing support 26.l In order tomaintain the gears 35, 36 and 3'7 in proper alined position with thegears 28, 29 and 30, they are closely but rotatably Aconfinedbetween-the bearing 39at one en d of theA housing -and the intermediatebearlngsupport'ZS. Y i I At lone end portion of the hollow shaftadjacent the bearing 39, a. shifting vyoke 52 (Figs. 1 and 2) which isnon-rotatable,-with respect tothe hollow shaftfisprovided with radiallyinwardly projecting pins 53 rigidly secured therein with their innerendsgilush withthe bottomot an outer annular groove55 of a-collar y56for operating the latter.' This yoke is connected through the 'medium ofawire 57 to a lever 58 pivoted upon a steering post or column 59 ofanautof line soV

outer ends 'flush with the bottom of the*groove and their inwardlyprojecting ends extending through slots 67 disposed in an axialdirectionf or." longitudinally in the cylindrical wall ofl..t he hol.Cam grooves 68fo`rmedin the, outer circumferential portions' of theshifting low shaft 38.

core 69 are engaged by the-end of the pins66 and are helical in form,although occupying only` `se"g has beenrotated through an angle ofdegrees ments of helices of suiiicient extent to cause rela--` tiverotation of the hollow 'shaft `and shifting core through an angle of 60degrees when "the cam 66 is moved from one end of then slot 67 totheother.' annular'plug 70 screw-threaded into the end of the shaftiSSabutsthe outer end ofthe shifting core 69, anda secondannular plug 72rigidly'niounted insidethe shaft serves Aas an abutment for'the innerendl of the* core '69. Intermediate portions of the core areipro'vi'dedWith keys 73 which jslidablyengage "keyways-75 in a rod 76 that isaxially movable-relative to both the coreand the hollow shaft.v

` The outeren'd of the rod 76 is provided witha collar` 77 rigidlymounted thereonafnd `a yoke'78 having 'lingers 79 engaged in an annulargroove 80 /to provide for axial movement lofthe rod re` -gardless ofWhether or not thes'haft 38 is rotating'f'fAn actuatingmember 82 -leadsfrom' the yoke to the lever 58 andthe yoke isoperable to move the rod byactuating the lever.V Theinner endipfortion of the rod 76 has-"aseriesof radially disposed arms 83 rigidly mounted thereon andis 'providedWith integral cani 'fingers 85 extending in anaxial direction beyondHthe adjacent edges of a series lofpartially cylindrical guide lugs86'form'ed integrally at thefend portion of the rod and spaced aboutvtherod at'intervals of120 degrees.Y 'Asbest shown in Fi'g.*'5, the outersurfaces of ,thesel cylindrical lugs arefadaptedto contact complementalrounded'innersurfaces of a series of dogs 87 that are movable radiallyinwardyl l'y' and outwardlythrough'slots *88y in the cylindri-v'cal'wall'of the shaft '38 and are further'provided Withv outeroppositely beveled 'faces k89."-"'i'Illfle'se dogs are also spaced aboutthe axis of vthefsh'aft 38 at' intervals of '120 degrees.

Three sets of dogs'87, 90 and 92are disclosed "2 in `this embodiment lofthel invention, and since their structurer and operation are identical,v'the same reference characters' a're'employed for'des'- ignating"thedet'ails of each.f"fCam grooves 93 inthe dogs arepadapted to 'receivethe cam n gersy 85ofl the radial arms 83, and when the' rod 76 isturnedrelativeto the shaft'BS thrbughfan angle of 60"Vdegree`s inva1counter-clockwise'di rection, as viewed inFig'; 5, thefdogsl'are drawninwardlytofollow the o'uter'- cylindrical guiding surface of the lugs86: At theconclusionoflthis movementl the inner extremities" dr'surfaces of the dogs fit between thev lugs 86 against' the sur'i face ofthe rod 76 and theirouterextremities del ned by the' 'ev'eled -facesV89`are` flush withf'the circumferenceibtthe shaf't3`8f Y? -u-zi Eachdog is yieldably heldin-lits inward position-by means-of a ball'95that-engages-'inthis position into a recess 96`in` the end vfaceffeachdog andiis mounted in a recess '971 formed fin the wall =of the shaft38.A'compressio'n spring 98 '3 power to-the driven shaft can be transmittedvselectively throughthe medium of any pair of gears 2 8-`-.35',29;-'36`o'r 30-37, depending upon theposition 'of the cam fingers 85 and lugs 86that are-Imovable-axially in the shaft by movementof the actuating lever77 after the rod 76 bythe operation of 'the core 69, Fo-r the sake off'convenience the pairs of gears 28-35, 29-36 and 30- -37 arereferred toas driven gears.

" VThe inner end portion-'of the rod 76 is provided withafcentraloiraxial` bore 103 for slidably and rotatably receiving oneyend portion'o-f a smaller rod 105,5 an" intermediate portion of'whi'chis journalled in a transverse partition 106 formed in an intermediatevportion of the hollow shaft 38.' The other .orbuter end portion of-therod 105 is mounted in a bearing 107 of a housing section 108 secured, asindicatedat 109, to the principal hous` mg 20..., .7,

As best shown in Figs.` 1 and 12,v a worm 110 formed on the rod 105inside the housing section meshes with a gear 112 that is carriedrigidly upon an actuating shaft 113`journalled, as indicated at 115,3invthe housing section. This rod is connccted for rotation WithinVpredetermined' limits by actuating a lever 116 that is rotatablymounted, as indicated at 117, upon the steering post 59, and an arcuatesegmental vgraduated bracket 118 is also mounted rigidly upon thesteering post for engagementw'ith'detents 119 and 120 of the lever thatare`eng'ageable-i-n notches `122 and 123, re.- spectively', on oppositesides ofV 'the arcuate bracket*118. The lever'116 is connected to theactuatingy shaft 113` for rotation thereof concurrently with theactuation ofthe lever.

A'portion of the journal bearing 107 supports telescoping cylindricalsegments'125, 126 and 127 that .are extensible vlongitudinally alo-ngthe vrod 105" inf' slightly spaced relation thereto. cylindricalsegment125 which serves as' a support'forthe other segments is anchored in thebearing-107QA 'Inwardly turned'langes 128 and 12'9y of-thecylindrical-segments 125 and 126,V respectively, provide for' propernestingof the seg` ments in their telescoping relation. The inner end ofthe segment 127 is rigidly secured to a collar -1'31isurroundingthe"rod"105.' f

y"l-"ins 130 lprojecting rigidly from the inner circumferenceof thecollar 131engage in a pair of helical grooves1Z 2-fo"rrnedv withrelatively high pitch ein the rod V`105;, landa pair of trlunnions`133rigidly moiinted in an annular flange 135 of the collar are' disposedinwardly inlanannulargroove 186 formed in a reduced end portion 1,37 ofa 'cam block :l50lto' provide for yrelative rotation between the .collar131 and-the cam block. V'I'herod 105- projects axially through the camblock'in slidable and journalled relation. Asbest shown in Figs. 6 andy14, a plurality'or" radial flanges 152 rfor-med integrally-upon `thecam block are provided` with cam faces 153.` One end portion of the camblocl isuin the form of'a body 155 pro- The outer 'I iii-5 lvi'din'gVcuter cylindrical surfaces slidably engagv ing the innercylindricalsurface of a shifting cage 154 and'is formed with'ilattenedportions 156 from which the outer edges of the flanges project. Thisbody is likewise provided with cam faces 157 spaced from the cam faces153 and-parallel, respectively, to the latter. Driving dogs 158 mountedupon the cam block are providedwith inner central guiding grooves 159that flt upon the ilanges 152 and are further provided with outerbeveled faces 160; Outwardly inclined cam surfaces 162 defined by theinside surface of the grooves 159 in the dogs are adapted to slide uponthe cam surfaces 153. These dogs 158 are also provided with side grooves163 having inclined cam groove portions 165 that are aligned with ngers166 projecting rigidly from brackets 167 rigidly secured vto the camblock. A cam surface ladjacent the extremity of each dog issubstantially parallel to the cam groove portions In the relativemovement of each dog 158 upon the cam block, to the left, as viewed inFig. 14, from its position' upon the flat surface 156, the finger 166travels along'the groove 168 until it reachesV .the inclined cam portion165 :and by further relative movement, the dog is drawninwardlyradiallyby the pin until it rests upon inner fiat surfaces 169 'of the camblock. In the opposite relative movement of these members Ythe cam faces153 and-157 contact the cam faces 162 and 168, respectively, to move thedog radially outwardly to the position shown in Figs. 6 and 14. f

Slots 170 in the Wall` of the cylindrical shifting cage 154 are sopositioned that the dogs always remain at least partially therein andare adapted to be moved outwardly therein when the cam. block is movedfrom its position shown in Fig. 7 toward the inner wall 173 of the-cage.Similar slots 175 in the wall of the hollow shaft 38 register with theslots 170 in a number of relative positions of the cage and shaft.Although the cam block is axially'slidable in the shifting cage 154, itis prevented from relative rotation therein by means of the dogs 158portions of which always remain in the slots 170, and by means of thebrackets 167 which travel in the grooves 176 in the inner surface of thecage. Longitudinal grooves 177 formed in the inner wall of the hollowshaft 38 slidably receive spline members 178 (Fig. 8) projectingintegrally from the outer surface of the cage to insure concurrentrotation of the shaft and cage, but permitting relative longitudinalsliding movement when the cage and shaft 38 are not Alocked together bythe dogs vOne end of apin .179 thatis'rigidly screwthreaded into the camblock 150Y adjacent the collar 131 extends in an'axial direction.l andin the position of the. cam block as shownin Fig. 7, it extends throughan opening 180 in the end wall 182 of the cage 15e. `Inmoving it to,this p'sition from the position shown.l in Fig; 6, an outer head 183ofthe pin, which'is slightly rounded and formed withan annular groove185, engages a cam bar 186. having slots 187 therein .for guiding itupon screws 188 mounted in the end cage wall 182. This cam bar has atits end opposite the head a cam'face 189 that'actuates head 190 rigidlysecured upon the end of a rod 192 to move the latter longitudinally tothe right, as viewed in Figs. Band 7, in an opening 193 in the cage wall182 and in .a bearing recess 195 formed between adjacent contactingwalls of the cage and cam block 150. An intermediate portion of the rod192 has a coil spring 196 surrounding it and connected thereto at oneend, as indicated at 197. `The other end of the spring abuts `the innersurface of the wall 182 and resists movement of the `rod to the right` Aslot 198 in the wall of the cage provides access to the spring, and asecond slot 199 at the otherv end of the-case slidably receives a lug200that is secured to the end ofthe rodl opposite the block, 190. ItYwill be observed that thelength of the slot 199 is at least twice thethickness of `the lug 200.

A recess 202 in the lower surface of the lug 200 has a relatively narrowinner portion 203 flared outwardly at its mouth to receive-a stiff wire205 which normally vis disposed in a groove 206 formed longitudinally'in the inner,` wall of the hollow shaft 38. A plurality of balls 207formed 'integrally at intervals upon the wire normally are disposed inrecesses 208 communicating With-the groove 206 and constituting enlargedportions thereof. Ther outer extremites of lug 200 defined by the recess202 straddle. the Wire and the' recess 202-registers with orreceives thewird When the wire is in the groove 206 and the balls 207fare in therecesses`208, the flared mouth ofA the recess 202 can be moved over `oneofthe balls without striking' it. In vthis position? the lug 200normally covers one of the balls andprevents thewire from beingaccidentally displaced. It isonly when the cam face `189 actuates the'head 190 of the rod 192 to its position shown in Fig. 7 that the wire205 and balls 207canjbe displaced from thev groove' 206. However, if thewire is moved to the position shown in'Fig. *l* longitudinal movement ofthe rod 192 and lug 200 to the left causes abutting contact'of the lugagainst one of the balls. j

As best shown in Figs. 1 and 2, the inner end of the Wire 192 'isdisposed in a recess 209y of the hollow shaft, and the other end isconnected to an annulus 210 having an outer annular Vgroove 212 and a.series of headed pins 213 supported in the end -of the hollow shaft 38.The annulus is slidable axially upon the pins218A 'and is 'constantlyurged toward the end ofthe shaft by means 'of springs 215 having theiropposite ends abutting the vannulus and heads 216 of the pins.

A yoke 217 pivoted, as indicated at 218, upon the housing'108isconnected tothe steering post lever 1'16 by' means of a wire 219'throughwhich the yoke is operable by pressing'a button 220 slidably mountedinthe endpi they lever.' rIn order to provide movement ofthelvvir'e"192'and balls '207 out of the groove 206, the annulus 210 is' actuatedoutwardlyv and the ballsf207 then ride Aoutwardly against thewalls ofthe' recesses 208. A complemental groover'221registering with thegroove"206."is formed along the lower'circumferentiall portion of the'cage l5/tand provides space for displacement ofl the ballsfrom therecesses 208.'l Referring Sto Figs. 1 and Sto'lO, the slots 175v of' thehollow shaft arei alinedv tov register with recessesz 222 in drivegears"225,226, 227 and 228, and a reversing gear 229".v Thewalls oftherecesses 222 are beveled to conform to the beveled faces 160 of thedogs'158, and'the'bevelingbegins at the inner bearing surface ofi eachgear, as findica'ted in broken lines -on opposite sides of the edge 15enewV in ing'. 9'. The dogs k15s 'are movable Vinto engagement intotherecesses 'in any one of these gears to 'drive itindividually. A seriesof gears 230, 231, 232 and'233 of different sizes 'supported rigidlyupon a drive shaft234;

mesh with dinerent size gearszzs, 226, v227 and 150 inol 228respectively, and the reversing geai` 229 meshes with an intermediategear 235 which in turn meshes with a gear 236 rigidly secured uponl thedrive shaft 234. A suitable journal member 237 carried by the bearingsupport 2 6 rotatably supports the intermediate gear'2`35. One end ofthe drive shaft-234 is journalled in the bearing and it has vanintermediate journal bearing 238 in the wall of the housing 20 oppositethe bearing'23. This shaft is adaptedto be connected in any suitablemanner to a suitable source 'of power (not shown). YFor the sake ofconvenience, the pairs of sets of gears 225-230, 226-231, 227-232,228-233, and the reversing gears 229-236 are referred to as-drive gears.

In the operation of the transmission gearing described' above, it 'willbe observed that each vengaging pair of intermeshing gears is arrangedfor constant intermeshing relationship, and vthat the driving andcontrol of each pair of gears 'iseffected by operating the mechanismcontained inside the hollow shaft 38. After power has been applied tothe drive shaft 234 to begin-Vrotation thereof, and the various Ypartsare in the operating position indicated in Fig. 1, the three pairs 'ofgears 28-35, 29-36 and 30-37; are continuously rotated and the dogs 87(Figs. 1 and 2) are .disposed through the slots 88 into the recesses 100of the gear 36. If it is vdesired to change the gear ratio bytransferring the driving force from the gears 29-36 to either of theother pairs of gears 28-35 or 30-37, the collar 56 is moved to thebroken line position (Fig. 2) thus providing` relative rotation of theshaft 38 and the core 69 through an angle of 60 degrees without inter.fering with the rotation of the shaft 38. This actuation through the rod76 rotates or moves the cam fingers along `the cam grooves- 93 in acounter-clockwise direction, as viewed in Fig'. 5, to drawV the dogs 87radially inwardly until thel beveled faces 89 are within the peripheraloutlineof the shaft 38. So far as concerns the transmission of powerfrom the intermediate shaft 38to the driven shaft 22, the'gears 28-35,29-36 and 30-37 are then in neutral relation and the collar 56 can besecured in'this position if it is Aso desired for as long a period asnecessary. vIn connecting any of the gears to be rotatably driven by theshaft 38, Vthe rod '76 which is slidable in-the core 69 is axially movedby actuating the yoke 78. InY the movement of the cam arms 83 in acounter-clockwise direction through 'an angle of 60 degrees Afrom theposition shown in Fig. 5, eachl of these arms is then positioned betweenadjacent inwardly drawn dogs 87 and are movableA longitudinally eitherinwardlyor out# wardly'to alike -position either between the dogs 90 orbetween thedogs 92; Then-by movement of the collar 576 back to itsoriginal position, as shown in Fig. 5, the dogs are moved radiallyoutwardly to engage the gear with which they then register. It will beapparent that the transmission of power to the shaft 22 from theshaft38-is a matter of selection with respect to the positive connectionofi any of the pairs of'gears through the medium of any of the sets ofdogs 90. 87 or 92; -Assuming the parts of the transmission to` be intherelationship shown in Figs.A 1 and 6, in

transmitting power tothe intermediate shaft 38 from driving shaft 234,the dogs 158 extending through the vslots 170 and V175'positively engagethegear 228 inthe recesses 222 for transmission of power through thegear 233 from-the driving shaft. Y When itis desired to change the gearratio by transmitting the power through the` pair of' gears 227-232 fromthe driving shaft, the worm gear 112 is actuated to rotate the helicallygrooved rod 105. A predetermined degree of rotation of this rod causesthev pins 130 to travel 'in the helical grooves 132 and since the collar131 is non-rotatable while the hollow shaft 38, together with theshifting cage 154, -is rotatable as a unit, the pins 133 draw therotating cam block 150 with the collar until the pin 179 is extendedthrough the opening 180 and engages the end of the cam bar 186 to causethe latter to snap into the groove 185 of the pin. The cam block 150 andthe cage 154 are then temporarily and yieldably held together as a unitby the pin 179 and cam bar, and further turning of the helically groovedrod `moves the eage-154 and blockv 150 concurrently. During the movementof the cam block 150, as just described, the inner surface of the dog158'slides upon the'surface 156 of the cam block and the pins 166 engagethe cam slots 163 and 165 progressively to draw thedogs inwardly untiltheirl outer surfaces are within the peripheral boun-` dary of the shaft38. It is only after' this opera` tion that the cage 154 and block`150can be' moved concurrently, or otherwise along the rod 105. Furtherrotationof the rod v105 in either direction moves the cage`154, togetherwith the camY block,'until it registers with the opening 222 in one ofthe gears 225, 226, 227 or 229.1 f f' In order to insure properregistering of the dogs 158 with the slots 170, 175 and the recesses 222for any of these gears,lthe cage is'moved to aposition slightly to theright of any of these slots, the position of which can be determined bsuitable graduations, such as the notchesfdis` closed on the arcuatebracket 118, and then the yoke l212 and annulus 210 are actuated to drawthe wirev 205 outwardly' until the balls 207 ride outwardly on the wallsof the recesses 208 to the position shown in Fig. 7. 'With the ballsheld in this position the rod 105 is rotated to move the gear shiftingcage 154 to the left as viewed in' Fig. 7 and the lug 200 will then bestopped, after compressing the spring 196,'by one of the balls 207according to the location of the gear within which it is desired toinsert the dogs. While the lug 200 is abutting the ball v207 topreventfurther movement of the cage, the rod 105' is further rotated inthevsame direction to move the cam block 150 inside the cage to theleft, as viewed in Fig. 7,'thereby releasing the head of the'yieldablyheld pin 179 from the cam bar v186 and causing the cam faces 162A and168 of the dog lto ride outwardly upon the camV faces '153 and 157 ofthe cam block. 'Thus driving engage-l ment of the shaft 38 with the gearis provided through the dogs 158 as they enter the recesses 222. 5 f

"Ihe' same kind of operation is provided'to reverse the direction ofrotation of the interme diate shaft'38A and drven'shaft 22by engagingthe dogs in the same manner with therecesses 222 of the reversingA gear229. It is ofcourse tobe understoodfthat the gearsrare in neutralrelation when the cam block 150 has withdrawn the dogs 158 from therecesses:222to `theffposition indicated in Fig...7. After the rdogs havebeen engaged with any of the gears as described the yoke 212 Visactuated back to its original po.- sition asshown Ain Fig. l Ytoreturnthe balls 207 and wire 205 into the groovev 206 andrecesses 208and the rod 192 is released to resume-its vpositionas shown in Fig. 6under the influenceof the spring 196 whereby the lug 200 covers one ofthe balls 207 and thus prevents accidental displacement of the wire andballs from the groove 206 and recesses 208.

From the foregoing description it will be apparent that power can betransmitted to the driven shaft 22 from the drive shaft 234 in suchmanner that three changes of speed can be effected through each pair ofgears 28-35, 29-36 and 30-37 and that each of these pairs of gears hasselective driving connection to any of the pairs of gears 225-230,226-231, 227-232, 228-233 and the three reversing gears 229- 235-236.Hence, the construction provides for at least twelve speeds forward andthree speeds in reverse. Since all of the engaging gears are constantlyin mesh including those arranged in pairs together with the three gears229, 235 and 236 for reversing the rotation of the shaft 234, it will beapparent that these various changes in gear ratio may be accomplishedwithout the use of the clutch, with the possible exception that theclutch should be used when starting the mechanism or when the reversegears are used. During the operation of the transmission the hollowshaft 38 is rotating and all of the gears are likewise rotating,although the several pairs of meshing gears are rotating at differentrates.

It is to be understood that the gears 28-35, 29-36 and 30-3'7 can beomitted and the shaft 38 can be considered as the driven shaft adaptedto be geared directly to a machine or vehicle axle (not shown) to beoperated.

In the description included herein, it is assumed that the source ofpower is applied to the drive shaft 234, but it is apparent that asuitable source of power can be applied to the shaft 22 which can beconsidered the drive shaft. Conversely, the shaft 234 is adapted toserve as a driven shaft to be applied to any mechanism or apparatus tobe operated through the transmission.

Although only one form of the invention has been shown and described indetail, it will be apparent to those skilled in the art that theinvention is not so limited, but that various changes may be madetherein without departing from the spirit of the invention or from thescope of the appended claims.

What is claimed is:

1. In a transmission structure, a hollow rotatable shaft having openingscommunicating radially with the interior of said shaft, a carriagemovable inside and axially of the shaft, gear engaging means slidablycarried by the carriage and movable outwardly through said openings,control mechanism slidable in said carriage for actuating said gearengaging means independently of the rotation of the shaft, said gearengaging means and mechanism having engaging portions operable to movethe gear engaging means positively inwardly or outwardly depending uponthe direction of movement of said mechanism, and means carried by theshaft and movable into and out of the path of movement of said carriagefor registering the gear engaging means with said openings.

2. In a transmission structure, a hollow rotatable shaft having openingscommunicating radially with the interior thereof, a carriage movableinside and axially of the shaft, gear engaging dogs carried by thecarriage and movable outwardly through said openings, a control memberslidable in said carriage for actuating said dogs, operating meansextending axially into the shaft for axially moving said control memberin the carriage, a device for yieldably anchoring said member in apredetermined position in said carriage, means for stopping the carriageat predetermined positions in said shaft, and cooperating with saidoperating means for releasing said member from said device.

3. In a transmission structure, a hollow rotatable shaft having openingscommunicating radially with the interior thereof, a carriage havingopenings for registering with the openings of the shaft, and movableinsideand axially of the shaft, gear engaging dogs mounted in thecarriage openings for selective projection through said shaft openings,a control member slidable in said carriage for actuating said dogs, saidcarriage having spaced portions for limiting movement of said member,actuating means extending axially into the shaft for axially moving saidcontrol member in the carriage, a device for yieldably anchoring saidmember to one of said portions, and means for stopping said carriage atpredetermined positions in said shaft and cooperating with saidoperating means for releasing said member from said device.

4. In a transmission structure, a rotatable shaft having an internalchamber, a carriage slidably mounted in said chamber, gear engaging dogsmovable outwardly from the carriage into gear engaging relation, meansslidably carried by said carriage for controlling the gear engagingmeans independently of the rotation of the shaft, and a member movablein the chamber into the path of movement of said carriage to stop thelatter at a predetermined position.

5. In a transmission structure, a rotatable shaft having an internalchamber, a carriage slidably mounted in said chamber, gear engaging dogsmovable outwardly from the carriage into gear engaging relation, meansslidably carried by said carriage for controlling the gear engagingmeans independently of the rotation of the shaft, and an elongate memberhaving a plurality of stops thereon movable into the path of movement ofsaid carriage for selective positioning of said carriage.

DANIEL J. TINDELL.

WILBER H. GOODENOUGH.

